In photographic elements for color diffusion transfer processes using dye-releasing redox compounds capable of releasing diffusible dyes as the result of the redox reaction with oxidation products of developing agents produced by the development of silver halides (such compounds are called "DRR compounds" hereinafter), the silver halide developing agents are either added to alkaline processing compositions or incorporated into the photographic elements in the form of their respective precursors. Representative silver halide developing agents suitable therefor are 3-pyrazolidinone type compounds and aminophenol type compounds. In addition to silver halide developing agents, certain alkali-soluble hydroquinones may be further added to the alkaline processing compositions as a competitive developing agent for the purpose of competing with the redox reaction of the oxidation products of developing agent with DRR compounds, as described in Research Disclosure, No. 15162, p. 79 (November, 1976).
In the present specification, the term "competitive developing agent" refers to a compound having a gradation controlling effect.
Research Disclosure, supra, discloses that hydroquinone, methylhydroquinone and t-butylhydroquinone are especially effective as a competitive developing agent. On the other hand, Japanese Patent Application (OPI) No. 51741/81 (the term "OPI" as used herein refers to a "published unexamined Japanese patent application") discloses that certain dialkylhydroquinones are added as a competitive agent to an alkaline processing composition. Those hydroquinones, although they may have their respective gradation controlling effects as described therein, suffer from the following serious disadvantages.
That is, unsubstituted hydroquinone has little effect on gradation control, while mono- or dialkylhydroquinones in alkaline processing compositions containing them have the difficulties that (1) the processing capacity is greatly changed with the lapse of time, (2) the so-called mottle is generated upon development-processing, and so on. In particular, phenomenon (2) tends to occur with greater probability the higher the viscosity of the developing composition containing a thickener such as carboxymethyl cellulose in a greater amount.